Dual jacking system and method

ABSTRACT

This invention relates to a dual jacking system and method for inserting and extracting tubulars, or the like into and out of a well, such as an oil or gas well, at a relatively high rate of speed.

BACKGROUND

[0001] This invention relates to a dual jacking system and method forinserting and extracting tubulars, or the like, into and out of a well,such as an oil or gas well, at a relatively high rate of speed.

[0002] In oil and gas well operations, long strings of tubulars, such aspipes, are inserted into and removed from wells at various times. Whentubulars are inserted into a well, a tubular is attached to the top of atubular string and the string is lowered into the well. When tubularsare removed from a well, a tubular is removed from the top of a tubularstring and the string is raised from the well. Depending on the depth ofa well, a string of tubulars may be thousands of feet long and manytubulars will need to be attached to or removed from the string tocomplete an operation. As a result, operations where a tubular string isinserted into a well and operations where a tubular string is removedfrom a well may take a relatively long time and require substantial manhours to complete.

[0003] It would be desirable to be able to reduce the amount of time andman hours it takes to insert tubulars into or removal tubulars from anoil or gas well. Accordingly, a dual jacking system and method asdescribed herein is needed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0004]FIG. 1 is an isometric view illustrating an embodiment of a dualjacking system shown in a first operational mode.

[0005]FIG. 2 is an enlarged isometric view of a portion of the system ofFIG. 1.

[0006]FIG. 3 is an isometric view of the portion of FIG. 2 shown locatedin the upper section of a tower.

[0007]FIG. 4 is an enlarged isometric view of another portion of thesystem of FIG. 1.

[0008]FIG. 5 is an isometric view of the portion of FIG. 4 shown locatedin the lower section of the tower.

[0009]FIG. 6 is an isometric view of the system of FIG. 1 located in thetower.

[0010]FIG. 7 is an isometric view of the system of FIG. 1 in a secondoperational mode.

[0011]FIG. 8 is an isometric view of the system of FIG. 1 in a thirdoperational mode.

[0012]FIG. 9 is an isometric view of the embodiment of FIG. 1 extendingover a wellhead.

[0013]FIG. 10 is a diagram illustrating an embodiment of a controlsystem associated with the system of FIG. 1.

DETAILED DESCRIPTION

[0014] Referring to FIG. 1 of the drawings, the reference numeral 10refers, in general, to a dual reciprocating mechanism, also referred toherein as a system, according to an embodiment. The system 10 includesan upper jack 20 including a head 22 to which one end of each of a pairof hydraulic cylinders 24 a and 24 b are connected in a manner to bedescribed. The hydraulic cylinders 24 a and 24 b operate in aconventional manner to reciprocate the head 22 in a vertical direction,as viewed in FIG. 1. The head 22 includes an engaging and disengagingunit, in the form of a slip bowl 26, adapted to engage and release atubular (not shown). Details of the head 22 and the slip bowl 26 will bedescribed later.

[0015] A lower jack 30 extends in a vertically spaced relation to theupper jack 20 and includes a traveling head 32 to which one end of eachof a pair of hydraulic cylinders 34 a and 34 b are connected, in amanner to be described. The hydraulic cylinders 34 a and 34 b operate ina conventional manner to reciprocate the traveling head 32 in a verticaldirection, as viewed in FIG. 1. The traveling head 32 includesvertically spaced engaging and disengaging units, in the form of a slipbowl 36 a and an inverted slip bowl 36 b, for engaging and releasing atubular (not shown). Each of the slip bowls 26, 36 a, and 36 b isindependently operable to engage or release a tubular at a given timeand, since conventional, will not be described in additional detail.

[0016] Referring to FIG. 2 of the drawings, the hydraulic cylinders 24 aand 24 b of the upper jack 20 extend vertically as viewed in thedrawing, and include two rods 40 a and 40 b, respectively, which movebetween a retracted and extended position relative to two barrels 42 aand 42 b, respectively, in a conventional manner. The respective upperends of the rods 40 a and 40 b connect to two pins 44 a and 44 b,respectively, which are mounted between two sets of flanges 45 a and 45b, respectively, on opposing sides of the head 22 to allow rotationalmovement between the head 22 and the hydraulic cylinders 24 a and 24 b.

[0017] Linear position transducers 46 a and 46 b are attached to thehydraulic cylinders 24 a and 24 b , respectively, for detecting andtracking the position of the upper jack 20. The use of the linearposition transducers 46 a and 46 b will be described in additionaldetail below. The head 22 includes guides 48 a and 48 b mounted on anupper portion of the head 22 and guides 48 c and 48 d mounted on a lowerportion of the head 22. The function of the guides 48 a, 48 b, 48 c, and48 d will be described in additional detail below.

[0018]FIG. 3 depicts the upper jack 20 located in an upper tower section50 which is formed by a plurality of vertical and horizontal structuralmembers in a conventional manner. The upper tower section 50 includestwo vertically spaced, opposed rails 52 a and 52 b as well as twovertically spaced, opposed rails 54 a and 54 b spaced from the rails 52a and 52 b. Each of the guides 48 a and 48 d of the upper jack 20 extendbetween the rails 52 a and 52 b in engagement therewith; and each of theguides 48 b and 48 c extend between the rails 54 a and 54 b, inengagement therewith to permit vertical movement of the head 22 relativeto the upper tower section 50.

[0019] The hydraulic cylinder 24 a is mounted between the rails 52 a and52 b and the upper end of the barrel 42 a attaches to the rail 52 a at apoint 56 a, and to the rail 52 b at a point 56 b. The hydraulic cylinder24 b is mounted between the rails 54 a and 54 b and an upper end of thebarrel 42 b is attached to the rail 54 a at a point 58 a and attaches tothe rail 54 b at a point 58 b.

[0020] Referring to FIG. 4 of the drawings, the hydraulic cylinders 34 aand 34 b of the lower jack 30 also extend vertically as viewed in thedrawing, and include two rods 60 a and 60 b, respectively, which movebetween a retracted and extended portion relative to two barrels 62 aand 62 b, respectively, in a conventional manner. The respective lowerends of the barrels 62 a and 62 b are connected to two tabs 64 a and 64b, respectively, which are mounted between two sets of flanges 65 a and65 b, respectively, on opposing sides of the traveling head 32 to allowrotational movement between the traveling head 32 and the hydrauliccylinders 34 a and 34 b, respectively.

[0021] Linear position transducers 66 a and 66 b are attached to thehydraulic cylinders 34 a and 34 b, respectively, for detecting andtracking the position of the lower jack 30. The use of the linearposition transducers 66 a and 66 b will be described in additionaldetail below. The traveling head 32 includes guides 68 a and 68 bmounted on an upper portion of the traveling head 32 and guides 68 c and68 d mounted on a lower portion of the traveling head 32. The functionof the guides 68 a, 68 b, 68 c and 68 d will be described in additionaldetail below.

[0022]FIG. 5 depicts the lower jack 30 located in a lower tower section70 which is formed by a plurality of vertical and horizontal structuralmembers in a conventional manner. The lower tower section 70 includestwo vertically spaced, opposed rails 72 a and 72 b as well as twovertically spaced, opposed rails 74 a and 74 b spaced from the rails 72a and 72 b. Each of the guides 68 a and 68 d of the lower jack 30 extendbetween the rails 72 a and 72 b in engagement therewith; and each of theguides 68 b and 68 c extend between the rails 74 a and 74 b, inengagement therewith to permit vertical movement of the traveling head32 relative to the lower tower section 70.

[0023] The hydraulic cylinder 34 a is mounted between the rails 72 a and72 b and is attached between the rails 72 a and 72 b at a point 76, andthe hydraulic cylinder 34 b is mounted between the rails 74 a and 74 band is attached to the rails 74 a and 74 b at a point 78 in aconventional manner.

[0024] Referring to FIG. 6, the upper tower section 50 is stacked over,and is connected to, the lower tower section 70 using pins 80 a and 80b, thus constructing a tower. The rails 52 a and 52 b and the rails 54 aand 54 b extend through the lower tower section 70 for guiding the upperjack 20 through the tower and the rails 72 a and 72 b and the rails 74 aand 74 b extend through the upper tower section 50 for guiding the lowerjack 30 through the tower.

[0025] Two tool joint sensors 84 a and 84 b are located above and belowthe upper jack 20 and the lower jack 30, respectively. The tool jointsensors 84 a and 84 b detect the presence of a tool joint attached to apipe string entering either the upper jack 20 or the lower jack 30. Thefunction of the tool joints sensors 84 a and 84 b will be described inadditional detail below.

[0026] Referring to FIG. 7, the hydraulic cylinders 24 a and 24 b of theupper jack 20 are shown in a fully extended position, and the hydrauliccylinders 34 a and 34 b of the lower jack 30 are shown in a fullyretracted position such that the head 22 is at a maximum distance fromthe traveling head 32.

[0027] Referring to FIG. 8, the hydraulic cylinders 24 a and 24 b of theupper jack 20 are shown in a fully retracted position, and the hydrauliccylinders 34 a and 34 b of the lower jack 30 are shown in a fullyextended position such that the head 22 is at a minimum distance fromthe traveling head 32.

[0028] In operation, the system 10 inserts and extracts jointed tubularsor continuous coiled tubing into and out of a well such as an oil wellor a gas well at a relatively high rate of speed. The system 10 may beoperated in two modes: a high speed mode and a low speed mode. Thesemodes of operation will be described below with reference to FIG. 1,FIG. 7, and FIG. 8.

[0029] In the high speed mode of operation, the upper jack 20 and thelower jack 30 move in opposing directions. In this mode, the hydrauliccylinders 24 a and 24 b of the upper jack 20 move to their fullextension at the same time the hydraulic cylinders 34 a and 34 b of thelower jack 30 move to their full retraction, as shown in FIG. 7. In thismode, the hydraulic cylinders 24 a and 24 b of the upper jack 20 alsomove to their full retraction at the same time the hydraulic cylinders34 a and 34 b of the lower jack 30 move to their full extension as shownin FIG. 8.

[0030] The operation of the system 10 may vary according to the pressureof a oil or gas well. In particular, the operation may depend on whetherthe system 10 is operating under pipe heavy conditions or pipe lightconditions. Pipe heavy conditions occur where the downward force causedby the weight of the tubulars equals or exceeds the upward force causedby pressure in the well. Pipe light conditions occur where the downwardforce caused by the weight of the tubulars is less than the upward forcecaused by pressure in the well. Operation of system 10 in the high andlow speed modes of operation will now be described under pipe heavyconditions.

[0031] To insert tubulars into a well in the high speed mode under pipeheavy conditions, the slip bowl 26 of the upper jack 20 engages atubular in the position shown in FIG. 7. The slip bowls 36 a and 36 b ofthe lower jack 30 remain disengaged in this position. The hydrauliccylinders 24 a and 24 b of the upper jack 20 then move to their fullretraction at the same time the hydraulic cylinders 34 a and 34 b of thelower jack 30 move to their full extension to reach the respectivepositions shown in FIG. 8. In these positions, the slip bowl 36 a of thelower jack 30 engages the tubulars and the slip bowl 26 of the upperjack 20 disengages the tubulars. The hydraulic cylinders 24 a and 24 bof the upper jack 20 then move to their full extension at the same timethe hydraulic cylinders 34 a and 34 b of the lower jack 30 move to theirfull retraction as shown in FIG. 7 to effectively lower the tubularsinto the well. The process just described is repeated to continuelowering the tubulars into the well.

[0032] To extract tubulars from a well in the high speed mode under pipeheavy conditions, the slip bowl 36 a of the lower jack 30 engages thetubulars in the position shown in FIG. 7. The slip bowl 26 of the upperjack 20 remains disengaged in this position. The hydraulic cylinders 24a and 24 b of the upper jack 20 then move to their full retraction atthe same time the hydraulic cylinders 34 a and 34 b of the lower jack 30move to their full extension to reach the respective positions shown inFIG. 8. In these positions, the slip bowl 36 a of the lower jack 30disengages the tubulars and the slip bowl 26 of the upper jack 20engages the tubulars. The hydraulic cylinders 24 a and 24 b of the upperjack 20 then move to their full extension at the same time the hydrauliccylinders 34 a and 34 b of the lower jack 30 move to their fullretraction as shown in FIG. 7 to effectively raise the tubulars from thewell. The process just described is repeated to continue raising thetubulars from the well.

[0033] In the low speed mode of operation under pipe heavy conditions,the upper jack 20 and the lower jack 30 move in the same direction andeach carry a portion of the tubular load. In this mode, the hydrauliccylinders 24 a and 24 b of the upperjack 20 move to their full extensionat the same time the hydraulic cylinders 34 a and 34 b of the lower jack30 move to their full extension. The upper jack 20 is shown in thisposition in FIG. 7, and the lower jack 30 is shown in this position inFIG. 8. The hydraulic cylinders 24 a and 24 b of the upper jack 20 alsomove to their full retraction at the same time the hydraulic cylinders34 a and 34 b of the lower jack 30 move to their full retraction. Theupper jack 20 and the lower jack 30 are shown in these respectivepositions in FIG. 1.

[0034] Referring to FIG. 9, a stationary slip bowl 90 a and an invertedstationary slip bowl 90 b is mounted over a wellhead 92. The stationaryslip bowl 90 a is used in the low speed mode of operation under pipeheavy conditions, and it will be assumed that it engages the uppertubular of the tubulars to be extracted from the wellhead.

[0035] To extract tubulars from the well in the low speed mode underpipe heavy conditions, the slip bowl 26 of the upper jack 20 and theslip bowl 36 a of the lower jack 30 engage the tubulars when thehydraulic cylinders 24 a and 24 b of the upper jack 20 and the hydrauliccylinders 34 a and 34 b of the lower jack 30 are in the fully retractedposition as shown in FIG. 1. The stationary slip bowl 90 a thendisengages the tubulars. The hydraulic cylinders 24 a and 24 b of theupper jack 20 and the hydraulic cylinders 34 a and 34 b of the lowerjack 30 then move to their fully extended position at the same time toeffectively raise the tubulars out of the well. Once in these positions,the stationary slip bowl 90 a engages the tubulars, and the slip bowls26 and 36 a disengage the tubulars. The hydraulic cylinders 24 a, 24 b,34 a, and 34 b then move to their fully retracted position at the sametime to repeat the process.

[0036] To insert tubulars into a well in the low speed mode under pipeheavy conditions, the slip bowl 26 of the upper jack 20 and the slipbowl 36 a of the lower jack 30 engage the tubulars when the hydrauliccylinders 24 a and 24 b of the upper jack 20 and the hydraulic cylinders34 a and 34 b of the lower jack 30 are in the fully extended position asshown in FIG. 7 with respect to the cylinders 24 a and 24 b, and in FIG.8 with respect to the cylinders 34 a and 34 b . The stationary slip bowl90 a then disengages the tubulars, and the hydraulic cylinders 24 a and24 b of the upper jack 20 and the hydraulic cylinders 34 a and 34 b ofthe lower jack 30 are moved to their fully retracted position at thesame time as shown in FIG. 1 to lower the tubulars into the well. Oncein these positions, the stationary slip bowl 90 a engages the tubulars,and the slip bowls 26 and 36 a disengage the tubulars. The hydrauliccylinders 24 a, 24 b, 34 a, and 34 b then move to their fully extendedposition at the same time and the cycle is repeated.

[0037] Although the low speed mode of operation under pipe heavyconditions is described above as using both the upper jack 20 and thelower jack 30, tubulars may be inserted or extracted in the low speedmode using only one of the upper jack 20 or the lower jack 30. Forexample, if only the upper jack 20 is used, system 10 will operate inthe low speed mode as described above with the exception that the lowerjack 30 will not move and the slip bowl 36 a of the lower jack 30 willnot engage the tubulars. Likewise, if only the lower jack 30 is used,system 10 will operate in the low speed mode as described above with theexception that the upper jack 30 will not move and the slip bowl 26 ofthe upper jack 20 will not engage the tubulars.

[0038] Operation of system 10 in the high and low speed modes ofoperation will now be described under pipe light conditions.

[0039] To insert tubulars into a well in the high speed mode under pipelight conditions, the head 22 of the upper jack 20 includes anadditional engaging and disengaging unit, in the form of an invertedslip bowl 96 shown in FIG. 9, adapted to engage and release a tubular(not shown). The inverted slip bowl 96 of the upper jack 20 engages atubular in the position shown in FIG. 7. The slip bowls 36 a and 36 b ofthe lower jack 30 remain disengaged in this position. The hydrauliccylinders 24 a and 24 b of the upper jack 20 then move to their fullretraction at the same time the hydraulic cylinders 34 a and 34 b of thelower jack 30 move to their full extension to reach the respectivepositions shown in FIG. 8. In these positions, the inverted slip bowl 36b of the lower jack 30 engages the tubulars and the inverted slip bowl96 of the upper jack 20 disengages the tubulars. The hydraulic cylinders24 a and 24 b of the upper jack 20 then move to their full extension atthe same time the hydraulic cylinders 34 a and 34 b of the lower jack 30move to their full retraction as shown in FIG. 7 to effectively lowerthe tubulars into the well. The process just described is repeated tocontinue lowering the tubulars into the well.

[0040] To extract tubulars from a well in the high speed mode under pipelight conditions, the inverted slip bowl 36 b of the lower jack 30engages the tubulars in the position shown in FIG. 7. The inverted slipbowl 96 of the upper jack 20 remains disengaged in this position. Thehydraulic cylinders 24 a and 24 b of the upper jack 20 then move totheir full retraction at the same time the hydraulic cylinders 34 a and34 b of the lower jack 30 move to their full extension to reach therespective positions shown in FIG. 8. In these positions, the invertedslip bowl 36 b of the lower jack 30 disengages the tubulars and theinverted slip bowl 96 of the upper jack 20 engages the tubulars. Thehydraulic cylinders 24 a and 24 b of the upper jack 20 then move totheir full extension at the same time the hydraulic cylinders 34 a and34 b of the lower jack 30 move to their full retraction as shown in FIG.7 to effectively raise the tubulars from the well. The process justdescribed is repeated to continue raising the tubulars from the well.

[0041] Referring to FIG. 9, the inverted stationary slip bowl 90 b isused in the low speed mode of operation under pipe light conditions, andit will be assumed that it engages the upper tubular of the tubulars tobe extracted from the wellhead.

[0042] To extract tubulars from the well in the low speed mode underpipe light conditions, the inverted slip bowl 96 of the upper jack 20and the inverted slip bowl 36 b of the lower jack 30 engage the tubularswhen the hydraulic cylinders 24 a and 24 b of the upper jack 20 and thehydraulic cylinders 34 a and 34 b of the lower jack 30 are in the fullyretracted position as shown in FIG. 1. The inverted stationary slip bowl90 b then disengages the tubulars. The hydraulic cylinders 24 a and 24 bof the upper jack 20 and the hydraulic cylinders 34 a and 34 b of thelower jack 30 then move to their fully extended position at the sametime to effectively raise the tubulars out of the well. Once in thesepositions, the inverted stationary slip bowl 90 b engages the tubulars,and the inverted slip bowls 96 and 36 b disengage the tubulars. Thehydraulic cylinders 24 a, 24 b, 34 a, and 34 b then move to their fullyretracted position at the same time to repeat the process.

[0043] To insert tubulars into a well in the low speed mode under pipelight conditions, the inverted slip bowl 96 of the upper jack 20 and theinverted slip bowl 36 b of the lower jack 30 engage the tubulars whenthe hydraulic cylinders 24 a and 24 b of the upper jack 20 and thehydraulic cylinders 34 a and 34 b of the lower jack 30 are in the fullyextended position as shown in FIG. 7 with respect to the cylinders 24 aand 24 b, and in FIG. 8 with respect to the cylinders 34 a and 34 b .The inverted stationary slip bowl 90 b then disengages the tubulars, andthe hydraulic cylinders 24 a and 24 b of the upper jack 20 and thehydraulic cylinders 34 a and 34 b of the lower jack 30 are moved totheir fully retracted position at the same time as shown in FIG. 1 tolower the tubulars into the well. Once in these positions, the invertedstationary slip bowl 90 b engages the tubulars, and the inverted slipbowls 96 and 36 b disengage the tubulars. The hydraulic cylinders 24 a,24 b, 34 a, and 34 b then move to their fully extended position at thesame time and the cycle is repeated.

[0044] Although the low speed mode of operation under pipe lightconditions is described above as using both the upper jack 20 and thelower jack 30, tubulars may be inserted or extracted in the low speedmode using only one of the upper jack 20 or the lower jack 30. Forexample, if only the upper jack 20 is used, system 10 will operate inthe low speed mode as described above with the exception that the lowerjack 30 will not move and the inverted slip bowl 36 b of the lower jack30 will not engage the tubulars. Likewise, if only the lower jack 30 isused, system 10 will operate in the low speed mode as described abovewith the exception that the upper jack 30 will not move and the invertedslip bowl 96 of the upper jack 20 will not engage the tubulars.

[0045] Referring to FIG. 10 of the drawings, the operation of the system10 in the high speed mode and the low speed mode is monitored andcontrolled by a computerized control system 100. The control system 100couples to the upper jack 20, the lower jack 30, the transducers 46 a,46 b, 66 a, and 66 b, and the sensors 84 a and 84 b using any suitablewired or wireless connection or connections. The control system 100 isalso coupled to slip bowls 26, 36 a, 36 b, 90 a, and 90 b and causes theslip bowls 26, 36 a, 36 b, 90 a, and 90 b to engage or disengagetubulars. The control system 100 may be located on the upper towersection 50 or the lower tower section 70 or another structure thatincludes the system 10 or may be located remotely from such a tower orstructure.

[0046] An operator of the system 10 selects either the high speed modeor the low speed mode and either to raise tubulars from a well or tolower tubulars into a well using the control system 100. The controlsystem 100 provides signals to the upper jack 20 and the lower jack 30to control the movement of the upper jack 20 and the lower jack 30 inthe manner described above according to the selections by the operator.

[0047] The control system 100 controls and monitors the position andspeed of the upper jack 20 and the lower jack 30 according to positioninformation received from the transducers 46 a, 46 b, 66 a, and 66 bshown in FIG. 2 and FIG. 4. The transducers 46 a, 46 b, 66 a, and 66 bprovide the control system 100 with position information regarding thepositions of the upper jack 20 and the lower jack 30, respectively. Thecontrol system 100 processes the position information to determine thespeed and the locations of the upper jack 20 and the lower jack 30.

[0048] The tool joint sensors 84 a and 84 b, shown in FIG. 6, detect thepresence of a tool joint attached to a pipe string entering either theupper jack 20 or the lower jack 30 and send detection information to thecontrol system 100. The control system 100 uses the detectioninformation to track the position of a tool joint as the tool jointmoves within the system 10. The control system 100 automatically adjuststhe position of the slip bowls 26, 36 a, and 36 b relative to the tooljoint to prevent the slip bowls 26, 36 a, and 36 b from engaging andpossibly damaging the tool joint.

ALTERNATIVE EMBODIMENTS

[0049] In an alternative embodiment not shown, the hydraulic cylinders34 a and 34 b may be inverted such that the rods 60 a and 60 b extend inan upward direction from the barrels 62 a and 62 b. In this example, therods 60 a and 60 b attach to the traveling head 32 similar to the waythe rods 40 a and 40 b attach to the head 22.

[0050] In addition, other embodiments are possible by inverting thecylinders and/or changing the mounting of the cylinder barrels and rodends.

[0051] It is understood that variations may be made in the above withoutdeparting from the scope of the invention. For example, mechanisms otherthan jacks and hydraulic cylinders can be used to reciprocate the slipbowls. Also, the slip bowls may be replaced by other units for engagingand disengaging the tubulars. Further, when the expression “tubular” isused it is meant to cover any type of tubular member such as coiledtubing, conduits, pipes, pipe joints, hoses, etc., and the reference to“tubular” in the singular does not preclude inclusion of a plurality oftubulars in the same string.

[0052] Although only a few exemplary embodiments of this invention havebeen described in detail above, those skilled in the art will readilyappreciate that many other variations and modifications are possible inthe exemplary embodiments without materially departing from the novelteachings and advantages of this invention. Accordingly, all suchmodifications are intended to be included within the scope of thisinvention as defined in the following claims.

What is claimed is:
 1. A system comprising: a first jack coupled to atower and comprising: a first slip bowl for engaging a tubular; and afirst and a second hydraulic cylinder for raising and lowering the firstslip bowl within the tower; and a second jack coupled to the tower underthe first jack and comprising: a second slip bowl for engaging thetubular; and a third and a fourth hydraulic cylinder for raising andlowering the second slip bowl within the tower.
 2. The system of claim1, wherein the first jack includes a head, and wherein the firsthydraulic cylinder and the second hydraulic cylinder are attached toopposing sides of the head.
 3. The system of claim 2, wherein the firstjack includes a plurality of guides attached to the head for guiding thehead along a pair of rails in the tower.
 4. The system of claim 2,wherein the first jack includes a position transducer for providingposition information associated with the first jack to a controller. 5.The system of claim 1, wherein the second jack includes a head, andwherein the third hydraulic cylinder and the fourth hydraulic cylinderare attached to opposing sides of the head.
 6. The system of claim 5,wherein the second jack includes a plurality of guides attached to thehead for guiding the head along a pair of rails in the tower.
 7. Thesystem of claim 5, wherein the second jack includes a positiontransducer for providing position information associated with the secondjack to a controller.
 8. The system of claim 1, further comprising acontroller for controlling the first jack and the second jack to raiseand lower each jack.
 9. The system of claim 8, wherein the controllercontrols the first jack and the second jack such that the first jack israised while the second jack is lowered.
 10. The system of claim 9,wherein the controller controls the first jack and the second jack suchthat the first jack is lowered while the second jack is raised.
 11. Thesystem of claim 8, wherein the controller controls the first jack andthe second jack such that the first jack and the second jack are raisedsimultaneously.
 12. The system of claim 11, wherein the controllercontrols the first jack and the second jack such that the first jack andthe second jack are lowered simultaneously.
 13. A method for raising aplurality of tubulars from a well comprising the steps of: engaging oneof the plurality of tubulars with a first slip bowl attached to a firstjack; extending the first jack to raise the plurality of tubularssubsequent to engaging the one of the plurality of tubulars with thefirst slip bowl; engaging the one of the plurality of tubulars with asecond slip bowl attached to a second jack subsequent to extending thefirst jack; disengaging the one of the plurality of tubulars with thefirst slip bowl subsequent to engaging the one of the plurality oftubulars with the second slip bowl; and extending the second jack toraise the plurality of tubulars subsequent to disengaging the one of theplurality of tubulars with the first slip bowl.
 14. The method of claim13, further comprising the step of retracting the second jacksubstantially simultaneously with extending the first jack.
 15. Themethod of claim 13, further comprising the step of retracting the firstjack substantially simultaneously with extending the second jack. 16.The method of claim 13, further comprising the step of disengaging theone of the plurality of tubulars with the second slip bowl subsequent tothe step of engaging the one of the plurality of tubulars with the firstslip bowl and prior to the step of extending the first jack.
 17. Amethod for lowering a plurality of tubulars into a well comprising thesteps of: engaging one of the plurality of tubulars with a first slipbowl attached to a first jack; retracting the first jack to lower theplurality of tubulars subsequent to engaging the one of the plurality oftubulars; engaging the one of the plurality of tubulars with a secondslip bowl attached to a second jack subsequent to retracting the firstjack; disengaging the one of the plurality of tubulars with the firstslip bowl subsequent to engaging the one of the plurality of tubularswith the second slip bowl; and retracting the second jack to lower theplurality of tubulars subsequent to disengaging the one of the pluralityof tubulars with the first slip bowl.
 18. The method of claim 17,further comprising the step of extending the second jack substantiallysimultaneously with retracting the first jack.
 19. The method of claim17, further comprising the step of extending the first jacksubstantially simultaneously with retracting the second jack.
 20. Themethod of claim 17, further comprising the step of disengaging the oneof the plurality of tubulars with the second slip bowl subsequent to thestep of engaging the one of the plurality of tubulars with the firstslip bowl and prior to the step of retracting the first jack.
 21. Amethod for raising a plurality of tubulars from a well comprising thesteps of: engaging one of the plurality of tubulars with a first slipbowl attached to a first jack; engaging the one of the plurality oftubulars with a second slip bowl attached to a second jack; extendingthe first jack and the second jack substantially simultaneously to raisethe plurality of tubulars subsequent to engaging the one of theplurality of tubulars with the first slip bowl and the second slip bowl;engaging the one of the plurality of tubulars with a third slip bowl notattached to the first jack or the second jack subsequent to extendingthe first jack and the second jack; disengaging the one of the pluralityof tubulars with the first slip bowl and the second slip bowl subsequentto engaging the one of the plurality of tubulars with the third slipbowl; and retracting the first jack and the second jack subsequent todisengaging the one of the plurality of tubulars with the first slipbowl and the second slip bowl.
 22. The method of claim 21, furthercomprising the step of disengaging the one of the plurality of tubularswith the third slip bowl subsequent to the step of engaging the one ofthe plurality of tubulars with the first slip bowl and the second slipbowl and prior to the step of extending the first jack and the secondjack.
 23. A method for lowering a plurality of tubulars into a wellcomprising the steps of: engaging one of the plurality of tubulars witha first slip bowl attached to a first jack; engaging the one of theplurality of tubulars with a second slip bowl attached to a second jack;retracting the first jack and the second jack substantiallysimultaneously to lower the plurality of tubulars subsequent to engagingthe one of the plurality of tubulars with the first slip bowl and thesecond slip bowl; engaging the one of the plurality of tubulars with athird slip bowl not attached to the first jack or the second jacksubsequent to retracting the first jack and the second jack; disengagingthe one of the plurality of tubulars with the first slip bowl and thesecond slip bowl subsequent to engaging the one of the plurality oftubulars with the third slip bowl; and extending the first jack and thesecond jack subsequent to disengaging the one of the plurality oftubulars with the first slip bowl and the second slip bowl.
 24. Themethod of claim 23, further comprising the step of disengaging the oneof the plurality of tubulars with the third slip bowl subsequent to thestep of engaging the one of the plurality of tubulars with the firstslip bowl and the second slip bowl and prior to the step of retractingthe first jack and the second jack.
 25. A system comprising: a firstmechanism comprising: first engaging means for engaging a tubular; andfirst reciprocal means for reciprocating the first engaging means; and asecond mechanism disposed in a spaced relation to the first mechanismand comprising: second engaging means for engaging a tubular; and secondreciprocal means for reciprocating the second engaging means.
 26. Thesystem of claim 25, wherein each of the mechanisms is in the form of ajack.
 27. The system of claim 25, wherein each engaging means is in theform of a slip bowl.
 28. The system of claim 25, wherein each of thereciprocal means is in the form of a hydraulic cylinder.
 29. The systemof claim 25, wherein the reciprocal means raises and lowers theirrespective engaging means, and wherein the second mechanism isvertically spaced from the first mechanism.
 30. The system of claim 25,further comprising a tower for supporting the first and secondmechanisms, and at least one rail on the tower for guiding the first andsecond engaging means.
 31. The system of claim 30, wherein each engagingmeans comprises a head, and at least one slip bowl mounted on the headfor engaging and disengaging the tubular.
 32. The system of claim 31,wherein the at least one rail on the tower guides each head.
 33. Thesystem of claim 32, further comprising at least one guide mounted toeach head for engaging the rail.
 34. The system of claim 25, furthercomprising control means associated with the first and second mechanismsfor controlling the first and second mechanisms so that the firstmechanism is moved in a first direction and the second mechanism ismoved in a second direction opposite the first direction.
 35. The systemof claim 34, wherein the control means also controls the first andsecond mechanisms so that the first mechanism is moved in the seconddirection and the second mechanism is moved in the first direction. 36.The system of claim 25, further comprising control means associated withthe first and second mechanisms for controlling the first and secondmechanisms so that the first mechanism and the second mechanism aresimultaneously moved in a first direction.
 37. The system of claim 36,wherein the control means also controls the first and second mechanismsso that the first mechanism and the second mechanism are simultaneouslymoved in a second direction opposite the first direction.
 38. A methodfor moving a tubular comprising the steps of: engaging the tubular by afirst mechanism; reciprocating the first mechanism and therefore thetubular; releasing the tubular from the first mechanism; engaging thetubular by a second mechanism; reciprocating the second mechanism andtherefore the tubular; and releasing the tubular from the secondmechanism.
 39. The method of claim 38, wherein the tubular isreciprocated in a substantially vertical direction and wherein thesecond mechanism is vertically spaced from the first mechanism.
 40. Themethod of claim 38, further comprising supporting the first and secondmechanisms on a tower.
 41. The method of claim 40, further comprisingguiding the first and second mechanisms relative to the tower.
 42. Themethod of claim 38, further comprising controlling the first and secondmechanisms so that the first mechanism is moved in a first direction andthe second mechanism is moved in a second direction opposite the firstdirection.
 43. The method of claim 42, further comprising controllingthe first and second mechanisms so that the first mechanism is moved inthe second direction and the second mechanism is moved in the firstdirection.
 44. The method of claim 38, further comprising controllingthe first and second mechanisms so that the first and second mechanismsare simultaneously moved in a first direction.
 45. The method of claim44, further comprising controlling the first and second mechanisms sothat the first and second mechanisms are simultaneously moved in asecond direction opposite the first direction.